Study The Protective Effects Of Polysaccharides From The Lycium Barbarum L On N-methy-N-nitrosourea Induced Retinitis Pigmentosa In Rats

Objective: The present study was designed to investigate the protective effect of Lycium barbarum polysaccharides(LBP) on N-methyl-N-nitrosourea(MNU)-induced photoreceptor cell apoptosis, and the involvement of the poly(ADP-ribose)polymerase(PARP) and caspase.Methods: Retinitis pigmentosa injury was induced in male Sprague-Dawley rats by an intraperitoneal injection of MNU 60 mg·kg-1. LBP were daily intragastrical administered seven days prior to MNU injection. Rats were sacrificed at 24 h and 7 days after MNU.Retinal morphologies, photoreceptor cells apoptosis, protein expressions were evaluated.Results: Morphologically, the outer nuclear layer was well preserved in the LBP-treated rat retinas. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-digoxigenin nick-end labeling(TUNEL) assays showed that LBP can suppress the loss of photoreceptor cells significantly, which was determined by the photoreceptor cell ratio at the central retina 24 h and seven days after MNU. Western-blot analysis demonstrated that the expression of procaspase-9,-7,-3 and cleaved caspase-9,-7,-3 were upregulated, and PARP were downregulated both 24 h and 7 d after MNU injection. LBP treatment significantly decreased protein levels of procaspase and cleaved caspase, increased the level of PARP on 24 h and 7 d.Conclusion: LBP inhibiting MNU-induced rat photoreceptor cell apoptosis and protecting retinal structure via the regulation of the expressions of caspase and PARP.